Field of the Invention
The present invention relates to a storage medium storing a display control program for controlling a display capable of providing stereoscopic display, a display control device, a display control method, and a display control system.
Description of the Background Art
With development of a display device and improvement in image processing performance, various displays providing stereoscopic display have been put into practical use. As a basic method of realizing such stereoscopic display (stereoscopic image), a method of using a pair of images (stereo images) having prescribed parallax that is obtained as a result of image pick-up of a common subject at different observation points has been known.
For example, Japanese Patent Laying-Open No. 2006-251683 discloses a stereoscopic image pick-up system for forming a stereoscopic image by using left and right video cameras to pick up a right parallax image and a left parallax image respectively. This stereoscopic image pick-up system can also perform zoom processing by controlling image pick-up lenses used in the left and right video cameras to vary a focal length.
In realizing stereoscopic display by using a pair of images (an image for left eye and an image for right eye) having parallax as disclosed in the prior art document described above, the image for left eye and the image for right eye are displayed on a display such that they are viewed by user's left and right eyes respectively. Then, a user may see a portion displayed in a manner overlapping between the image for left eye and the image for right eye, around a display surface of the display.
Namely, the portion displayed in a manner overlapping between the image for left eye and the image for right eye is a portion on which the user can readily focus. Therefore, parallax between the image for left eye and the image for right eye at the display surface of the display is preferably adjusted such that an object or the like on which a user wishes to focus is located at a portion displayed in a manner overlapping between the image for left eye and the image for right eye.
When zoom processing or the like as shown in the prior art document described above is performed, a range (a size or a position of a subject) displayed as the image for left eye and the image for right eye is varied. In general, it is considered that, in many cases, the user performs zoom processing or the like if he/she wishes to focus on a specific portion of the subject.
Here, as the size or the position of the subject displayed on the display is varied in accordance with zoom processing or the like, parallax on the display before zoom processing is different from parallax on the display after the zoom processing. Therefore, parallax of the portion that has been focused on by the user is altered when zoomed. For example, when zoom is performed from a state that parallax has been adjusted such that the portion focused on by the user is seen around the display surface, it is also possible that parallax of that portion that has been focused on is altered and that portion is seen at a distance from around the display surface, and a portion different from the portion on which the user wished to focus is seen around the display surface of the display.